Which is the best way to get better Xtal tuning

[Annie_he]

Hi NXP team,

     Now we are tunning the frequency error for bluetooth boards with KW45 solution.

     We get  two ways for tuning Frequency error.

     1. The first way is changing the value of internal capacitance, named Xtaltrim value in hardwareParameters in HCI_black box Firmwave.

  2. The second way is adding EXternal capacitance in Oscillator.

    We wanna ask you The difference between the two ways for Frequency tuning. If we wanna get better RF performence in Frequency accuracy test, which one is better for us.

    And here is our Default Frequency accuracy=118.5Khz, out of the limit(-20, 20)ppm. Would you mind give us some ideas about it, Thank you very much.

Best Regards,

Annie

[nxf77486]

Hello,

Thank you for contacting NXP support.

I appreciate the  information you proportionate. And I think that the following Application Note that contain a detailed RF evaluation report of the KW45.

Please let me know if this is the type of information you require or if there is anything else where I can help you.

[Annie_he]

Hello,

     Sorry, I did not describe my problem Clearly.

     Our problem is our dut is performening worst result in Frequency error, and how can tuning the Frenquency, and let us get correct Frenquency.

     For example, now we control dut to send a signal in 2440 Mhz for KW45 bluetooth funtion. But now we get the signal is 2440.11858Mhz, it is out of  the limit.

     How can we tunning to get more corrcect Frenqency?

[nxf77486]

Hello,

Thank you for clarifying the problematic.

In this case I would recommend to give a look into the Compact Planar Antennas for 2.4 GHz Communication. And to give a loo to chapter 7 of potential issues and check if you are not facing one of this problematic. Also this document explain in the chapter 10 some antenna design examples.

It is also recommended to validate that the antenna design consideration match with the recommendations on the Hardware Design Considerations for KW45B41Z.

Please let me know if there is anything else where I can help you

Please let me know if there is anything else where I can help you.